Catalytic hydrocarbon conversion process with the use of a moving bed at different temperature levels



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April 10, 1956 L. P. EVANS ET Al. 2,741,582

CATALYTIC HYDROCAREON CONVERSION PROCESS WITH THE USE OE A MOVING EEO AT DIFFERENT TEMPERATURE LEVELS Filed Sept. 19, 1952 2 Sheets-Sheet 2 70 @0IA/:N7 auf @00m/vr mf 1.9

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United States Patent O CATALYTIC HYDRCARBN CONVERSION PRDCESS WITH THE USE F A MOVING BED AT DHFFERENT TEMPERATURE LEVELS p v Louis P. Evans, wooabory, N. r., one .too n. ration,

Augusta, Kans., assignors to Socony Mobil Oil Company, Inc., n corporation of New York Application September 19,1952, Serial No. 310,458 A u i Claims. (Ci. 19e- 52) This invention pertains to the conversion of high boiling hydrocarbons to lower boiling hydrocarbons in the presence of particle form material. lt is particularly con# cerned with a process for cracking hydrocarbons boiling at a higher temperature than gasoline in the presence of a solid cracking catalyst to produce gasoline.

A large portion of the gasoline used today is obtained by converting suitably selected petroleum stocks, such as gas oil and the like, by contacting the gas oil with ad-V sorbent catalysts at temperatures of the order of 700- l000 F. and pressures usually of about 5-30 p. s. i. gauge. The heavy oil is converted to the lighter gasoline constituents in yields of about -50 per cent. It is cus tornary to pass the reactant material, in liquid or vapor form, through a gravitating bed or" the contact catalyst in areaction zone andtransfer the products to a separating zone where the gasoline is separated from the gas and heavier oils. The oil `is usually heated in a `furnace or heat exchanger prior to its introduction into `the reactor so that at least a substantial portion of the oil is converted to a vapor before itcoritacts thecatalyst. After the products are removedfrom the reactor, they are cooled in a suitable heat exchanger before being introduced'into the y synthetic crude tower for separation.` The cracking systemrequires, therefore, several pieces of complicated and expensive apparatus interconnected into a unitary group. Each piece of apparatus has its own thermal losses and these `thermal losses 'are cumulative. It is desirable to simplify the "apparatus required, decrease the number of pieces `necessary and make the cracking system more compact. i

It is a major object of this invention to provide an improved process in which high boiling liquid petroleum fractions may be converted to gasoline in a confined zone and substantially only gasoline and lighter products removed from said zone.

. It is a further objectof this invention to providean improved process for converting high boiling liquid petroleum fractions to gasoline which has high thermal It is a further object of this invention to provide `an. improved process for converting heavy hydrocarbons in the presence of a suitable contact material and separating substantially only gasoline and lighter material from the contact material.

These and other objects will become apparent from the following detailed description of the invention.

. In the preferred form of the invention, a granular con tact material is gravitated downwardly as a compact column with a cool contact material being supplied tothe top of thecolumn and a hot Contact material `being introduced `into the column at an intermediate level. A high boiling level hydrocarbon charge is introduced into the column below the point of introduction of the hot contact material. The hydrocarbon charge is cracked and passes` upwardly through the column to contact cooler catalyst inthe upper portion of the column. The flow rate and `temperatures of the hot and cold `catalyst u doit is,

ICC

charge and passedto a reconditioning and heating zone for subsequent reuse as nthe hot catalyst stream. The gasoline and lighter material removed from the top ofthe column are separated into gas and gasoline fractions and the gas may be recycled to the bottom of the column of catalyst to travel upwardly and extract heat from the catalyst in the lower portion of the column.` Heat may also be extracted from the lower portion of the column by means of indirect heat exchange coils. The cooled catalyst is then recycled to the top ofthe column.` u

Although a low activity catalyst may be used in the process of this invention, it is preferred to use a catalyst having high cracking activity and high heat capacity.

The catalyst may partake of the nature of natural or i p ..Figure l is an elevational view, partially in section, of

a unitary cracking system illustrating the invention.V

Figure 2 Ais a modified form ofreactor `also illustrating` the invention.

Referring now to Figure l, an elongated vertical .vessel 10 serves as the reactor, having any suitable crosssection,

such as round, square, rectangular. A kiln 1l is located? alongside the reactor it). A cool catalyst hopper l2 and a hot catalyst hopper 13 are located above the reactor iii, the cooi catalyst hopper being connected to the top of the reactor 10 by a conduit 14 and the hot catalysthopper being connected to the reactor at an intermediate level by the conduit 15. A withdrawal conduit lo is attached to the bottomof the reactor 10 and connected to the bottom of an elevator 11H The top of the elevator 17 is connected to thetop of the cool catalyst hopper `by the conduit i3. A conduit 19 connects with the reactor lli) at an intermediate levelbelow the point at which the conduit 1S is attached thereto. Conduit i9 connects to the bottom of airelevatorZtl. The top of the elevator 2i) is connected to the top of the kiln il by the conduit 2E. A withdrawal conduit ,22 is attached to the bottom of the kiln and con nectedto the bottom of an elevator 23. The top of the elevator 23 is connected to the top of the hot catalyst hopper by the conduit 24.

17, via conduit 18 to the cool catalyst hopper l2. The

catalyst is gravitated downwardly from the hopper 12 as` a compacted column which extends through the conduit 114 anduvessell to the` bottomof the elevator 17. A partition plate 25 i-s located in the upper portion of the reactor. Agroup of drop pipes 26 are attached to the plate 25 for transferring catalyst from the plate 25 to the top of the bed in the main portion of the: reaction zone. A seal gas is introduced into the top of the vessel 10 through the pipe 27 to prevent reactant vapors from rising upwardly through the drop pipes 26. A stream of hot catalyst is withdrawn from the bottom of the kiln l1 through the conduit 22 and lifted via the elevator 23 to a level frornwhich it hows through the conduit 24 to the hot catalyst hopper 13. The hot catalyst is gravitated as a compacted column from the hopper 13 through the conand is preferably introduced into the bed` of solids vin the .vessell .through .branch conduits 28 which all terminate at about the same elevation. Inverted funnel members 29 are attached'to the bottom end of these branch'conduitsto permit-ithe-hot solidstr'eams 'to enter. the reactorv freely,l funnels'29 to `provide for; intimate mixingof the hot stream with' the cold stream of solids and thereby providerv a uniform catalyst temperature across thecolumn. Oil feedA is introduced through the conduit 31 into thecolumn at a level beneath the level at which the hot catalyst is introduced. The inverted channels oranglc irons 32 are located across the vessel 1li:v so as toshield the oil: feed introduction. pipes.'V The oil feed, in liquid or vapor form,

rises upwardly throughthebedof hot solidsand is atl least partialycraclced to lighter hydrocarbons. When the.

tions condense to droplets.' The Vupward ilow rateiof the.

gaseous material may be sucient .to lift .andmaintain .the droplets in the column. Ring typevbaics 34 are. located in the upper portion ofthe vessel 10. The'baffles 34 have an upwardly directed innerwallwhich connectsl to the floor ci the battles to forma suitable trapv tray. The storage space ofthe trap tray is covered by dish-shapedv battles 55', which serve to keep the catalyst out of the trap tray. The. dish-'shaped baiiles .are open in. thefcenter or bottom, so as to permit free transfer of solids therethrough. .The liquid hydrocarbons accumulate in thecolumn and collect in the jtrap. trays. rlhe liquid hydrocarbons aredrawn.oflfthrough .theV conduits'. 35;' The Withdrawn; liquids are "laced under pressure by the pump 37, and may vbeheated, idesired', in the heater lconn'ectedminthe line 39. The heavy condensed hydrocarbons may be Withdrawn. through theconduit @il or passed downwardly through `the conduitfd. to the oilfeed linet for reuse .in the process.

Preferably, the liquid condensateis .recycled until it is converted toV coke or gasoline an'd'lighter' products. Where the upward gas flow through thecolumn is not suicient to hold the droplets of. condensed material in the upper portionV o the column, theliquid collection systemv must be arranged to cover a sufficient portion of the cross-section.

Bales 3l? are varranged` below the.

withdrawn .from Ythelbottom ofthe Vcolumn and recycledto the top of the cool catalyst hopper l2. The heated cycle gas is withdrawn from the vessel itl beneath the collection member 45. Some of this gas may be conducted via the conduit 62 to a level aboutthe same as that at which the oil charge is introduced into the column and introduced under the channels .or angle ironsV d3. The remainder of the cycle gas may be Withdrawn fromv the system through the conduit ed, cooled in the cooler 4, and pumped via the pump S back into the lower portion of the column for reuse as coolant fluid. It is possible to use liquid recycle; as a coolant lin this process. The recycle is separated? into heavy and light material. The'heavy recycle is lthen introduced intothe .column just below the level of hot solids withdrawal through conduit i9. The light recycle is introduced at a lower level.` A suitable-purge gas is introduced into the bottom of the column via the pipe 65.

An alternate arrangement of apparatus foripracticing the invention isshownonligure 2. The reactor 1l) isf suppliedcool catalyst by the'. conduit 14 and hot catalyst by theconduit 1S' and branehpconduitsrZS. Liquid'chargel isintroduced via. the conduit 31 at a lcvelsubstantiallya below the mixing baicstl and substantially abovefthe'. level of .a series ofiunnel-shapedcups 7d. The. cups ,are distributedfuniformly Vacrosstthe vessel and are connected to. the.. conduits il t'or removal of a sidestream of the; solids via the. conduit 19V to a kiln, not shown. Atrapi:

` tray'- is .showninztheupper portion of the vessel havinga of the vessel -so that recycle liquid is collected in largeV enough quantity. This can be done by use of a sulicientl number of trap trays or V-shaped collecting.troughs'dis.-

tributed across the vessel, shielded to'prcvent catalyst from:

enteringv the troughs.

A partition plate l42 is locatedacross `the-vessel 10 bcneath the level at whichth'e oil feed is introduced into'the. column. Drop pipes 43 andk 44are attached to this lplate.

The pipes 43 conduct catalyst onto a1 funnel-shaped col-'- lection member 45v Whicltconnccts at its lower end t0I conduit i9. This permits the removal of a stream of 'sollr ids from the column for transfer via the elevator 20 and from'thetop of the vessel 10 through the conduit33 lis cooled in' the cooler 54 and separated in a simple accumulator Liquid product isdiawn'fr'om the bottomN of the accumulator 5S through the conduit 56 andthe gas f istaken overhead via the conduit 57 to thercornpressor' 58. Some gas may be withdrawn as make. gas vi'a the conduit 59. The remaining-.gas under p ressureis recycled via' the conduit`60 to a'levclnearth'e bottom of the catalystlcolumn inl the' vessel 10. The-gas'is introduced und'erthe channelsll and'travels upwardly throughv the' bedot catalyst; Thetgasfislsubstantally'cooler than the catalystL and undergoes-'f heatI exchangev'vitlr the i catalyst,

iloor'75 Vandvertical .walld T he top of the wall ispconnectedto the'. inner wall of the vessel 10 by. a conical.y

screen' 77, suitably selectedtov prevent the solidmaterial. from.. entering thetrap. tray. ln placeof the singlerscreen; shownpadouble screen may be provided with provisions` for; iniecting steam. therebetweento clean the screens. when. desired. Theliquid. condenses `in the upper portionr. ottheicolumn.. The upwardgas dow may be just suicientt to suspendthedroplets at thelevel of the traptrayorf thetray mayk be designed to `catch the droplets asthey. fall'. The liquid iiows .through the screen 77 into the trap; tray and is removed therefrom as recycle stream in amannersimilar to that shown on Figure l. Alternativelyimv ternal conduits may be used to transfer the recycle stream downwardly from'the trap tray through the column toy ai dischargelevel in the lreaction portion of the bed. Thef` gasoline .and lighter material enters the cyclone separators;y 78' in the catalyst-free. area beneath the partitionplate 25'. Any` entrained liquidlin the vapor stream is separated in the cyclone separators and passed through the drop legs 79 into-the trap-tray. Thegas is withdrawn from the vesselltlvia thei conduit 33. The remainder ofthe systemk may be similar to that shown on Figure 1.V and is, hence, .not shown'in thisgure. Recycle gas, which hast been cooled, may be introduced into the bottomlof the column-via the conduit 80 to travel upwardly through the bed. of solids: The recycle gas cools thesolids, before= theyiare transferred viathe conduit 16 to the cool catalyst hopper. The gas is withdrawn from the column viathe.1 channels 81 and conduit 82. Additional cooling maybe obtained by cooling. coils 83. Alternatively all the coolingv maybe eiiected by use-of the cooling coils 83.v

Asan'illustration of the invention, a gas oil, having-1av boiling range of about 450 to l000 F., may be intro-V duced into acontinuous gravitating bedV of chrome bead contact-catalyst'at'an intermediate level at a ilow rate ofl about 7,500 barrels per day. Cool catalyst is added to theA top ofth'e column at a temperature of about 280 F. and ow 'rate'of about 280 tons per hour. The hotcatalyst is introducedinto the' column at about l0 feet below the top thereof at'a temperature of about 950 F. and flow-rate vof aboutl 430 tons per hour. The height of 'the' column'is about 45` feet and the cross-section about`260 square feet. The side stream of solids for the kilnI is withdrawnfrom thecolumn at a level about 10ifeet abovetheY bottom ofthe' column; Condensate is recycled at a ow rate of" about7,500 barrelsv per day and gas is recyamines 350 F. The hot catalyst `may be introduced into the' column at a temperature of about 900 to l,200 F. but preferably should be about 950 to 1,050 F. The separation of the hydrocarbons in the upper portion of thel column should be broadly such that the gasoline and lighter material is not less than 75 weight per cent of the products removed from the top of the column and preferably should be such that not less than 90 weight per cent of the product is gasoline and lighter material.

, The `process of this invention has many advantages over the prior practices, such as for example:

(l) Since `substantially all the product removed from the catalyst column is gasoline or lighter, no synthetic crudefractionating tower need be provided.

(2)` The cracked products are continuously removed from the cracking zone and the heavier than desired products are continuously recycled, resulting in improved overall yields of gasoline and decreased gas and coke formation.

(3) Since it i-s only necessary to supply heat to the process equivalent to the heat of cracking plus the heat of vaporization of the net product plus radiation losses, the thermal eiiiciency is hig (4) Since no heaters, vaporizing furnaces, synthetic crude towers, cracked vapor heat exchangers need be provided, the cost of apparatus for practicing the invention is lout-V` s It is intended that the scope of this invention be considered broadly to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit of the invention.

We claim: l

l. A process for the catalytic cracking of hydrocarbons to form a gasoline-containing product, which comprises: maintaining a downwardly gravitating, substantially compact bed of solid, granular adsorptive catalyst within a confined zone; supplying a stream of cool granular adsorptive catalyst to the upper section of said bed at a temperature within the range about 150 F. to 450 F.; supplying a stream of hot granular adsorptive catalyst at a temperature within the range about 900 to 1200 F. to an intermediate level in said bed in suliicient quantity that a substantial portion of said bed therebelow is maintained at an average temperature within the range of about 700 to l000 F.; introducing hydrocarbon charge into the bed below the level of hot catalyst supply and passing the charge through the bed to effect cracking thereof below the level of hot catalyst supply; passing vapors resulting from the cracking conversion upwardly through the upper section of said bed above the level of hot catalyst supply to effect heating ofthe catalyst in that section and coolmg of the vapors to a point where condensation occurs t0 the extent that of the remaining uncondensecl vapor at least 75 per cent boils within the gasoline boiling range and below; removing a vapor product, at least 75 per cent of which consists of material boiling within the gasoline range and below, from the upper section of said conned zone; continuously removing catalyst from the lower section of the bed as a mixture of catalyst particles initially supplied to the upper section of the bed and catalyst particles supplied at the intermediate level in the bed; passing a portion of the catalyst so removed to a conlined regeneration zone and regenerating the catalyst therein to recondition it for re-use in the reaction zone; returning catalyst from the regeneration zone to the bed as the hot catalyst stream; passing a second portion of the catalyst` removed from the bed into and `through `arcooling zone and `returning said second portion to the reaction zone as the cool catalyst stream. 4

2. A process' for the catalytic cracking of hydrocarbons, which comprises: maintaining a downwardly grav-1 itating, substantially compact bed of solid` adsorptive catalyst within a confined zone; supplying a lirst stream of solid adsorptive catalyst to the upper end of said bed at a temperature within the range to 450 F.`;`sup' plying a second stream of solid adsorptive catalyst at a temperature within the range about 900 to l200 F.` to an intermediate level in said bed to mix with the cata-l lyst in said bed at said level, said second stream being of sufficient quantity that a substantial portion of'said bed below the level of its supply is maintained at an average temperature within the range about 700 to l000 F.; supplying a hydrocarbon charge to the bed at a level below the level of supply of said second stream and passing said charge upwardly through the bed to` elect cracking thereof; passing the vapors resulting from` the cracking conversion upwardly through the portion of the bed above the level of supply of said second stream, whereby heat transfer occurs and a substantial portion of the products of conversion are condensed so that there remains as a vapor, material at least 75 per cent of which boils within the gasoline boiling range and below; withdrawing as vapor product said material re` maining in the vapor state after said condensation; withdrawing material condensed in `the upper section of `said bed from said confined zone separately of the vapors withdrawn; re-introducing a portion of the vapor prod` uctwithdrawn into said bed at a level adjacent the lower end of `the bed and cooling catalyst by means of` said;

portion of the vapor product; withdrawing catalyst as` a mixture of the catalyst particles initially supplied from said first and second streams from said bed at a level above the level of supply of said portion of the gaseous product and below the level of supply of said second stream and regenerating the catalyst so` withdrawn and returning it to said bed as said second stream; also removing catalyst as a mixture of catalyst particles initially supplied through said first and second streams from the lower end of said bed after it has been cooled by the introduced portion of the vapor product and returning said cooled catalyst to the upper end of said bed as said first stream.

3. The process for the catalytic cracking of hydrocarbons, which comprises: maintaining a downwardly gravitating, substantially compact bed of solid adsorptive catalyst of a size within the range 4 to 100 mesh within an elongated confined zone; supplying a rst stream of catalyst to the upper end of said bed at a temperature within the range 150 to 450 F.; supplying a second stream of catalyst at a temperature within the range 900 to l200 F. to an intermediate level within said bed to mix with the catalyst there; supplying a hydrocarbon charge to the bed at a level below the level at which said second stream is introduced and passing said charge upwardly through the bed to effect cracking thereof; maintaining said bed between the level of supply of said second stream and the level of hydrocarbon introduction at an average temperature within the range about 700 to 1000 F.; passing the vapors resulting from the cracking` conversion upwardly through the portion of the bed lying above the level of introduction of said second stream to eect heat transfer between vapors and catalyst, whereby a sufficient portion of the vapors are condensed so that there remains as a vapor a material at least 75 per cent of which boils in the gasoline range and below; removing vapor product, consisting of at least 75 per cent of material boiling within the gasoline range and below, from said zone at a level above said bed; withdrawing condensate formed in the upper section of said bed from the upper section of said bed 7` andretuming `iteto saidbed -'at AAaalevel below the -level of 'fsnpplyof fs'aidtsecond 'isti-earn; removing catalyst asV a mixture'4 of' 'particles linitiallyV supplied cfrom both o saidstreams from the lower section of-isaidbed;E regenerat-A ing a portion ofthe vcatalyst so removed 'and returning it "to/said bedfas saidsecondstream 'and' coolingv aneth:-

er portion Vof the, catalyst so rcmovedeand returning i it-A toV said` bed as said tir'st stream.A

4.' Arprocess for the catalytic'crackingofipetroleurne hyd'r'ocarbons, which1 comprises: maintaining adown- V wardlyggravitatingj substantially compact bed of solid adsorptive catalystofi'a size withimthe-rangeeaboutl to` 100'mesh Tyler `within vanv elongated :continedf zone;l

supplyingr'a, lirst streani-ofsaid cataiys't'at atemperature'Withinjhelrangetabout 200`1to 300 F, to Vthe-up per endof Asaid ibedg" supplying a -second' stream of 'said catalystat'a' temperature'Within-rthe range-about 900 to' withjk the'V catalystl uin vsaid bed at isai'd level;` 'supplying' a petroleum-,hydrocarboncharge boiling within the rangeabout 450-to'1000"l Fgto said'b'edat 'alevelbelow'the levelfofv` supplyf of saidf'second` stream; maintaining1the' average temperatureof Asaid bed `betweenth`e level of'hy'- dr'ocarb'on charge 4supply and-theelevel of 'supply of said Secondjfstream Within the range'about 700 to l000"F.`;

p assin'ghydrocarbonacharge upwardl'yjthrough; the bed' to `effect cracking lthereof Yin 'the region of the'bed below the level^ofl supply of saidgsecond-stream; passing the vapors'- formed fromv said Ycracking Vupwardly into the upper-portion'of lsaid bed laboveithe level of supply off range is condensed; withdrawing as a vapor product from 8 theiupper sectionl Aof saidA =bed\ awvaporv lstream `uin which at-1e'ast-90-\ perA cent--of' tbe material boils within-the` gasoline boiling range and below?vremovirigcondensate formedf inethe upper-section: ofl fsaid-bedtfrcm said "bed f Y at 'a 'level Ibelow* that-at which'fthevaporproduct is Lwithj drawn and recycling at least a portion of the-condensate so Aremoved -tosaid'bed atl a level below-thelevelfofsup plyl of saidsecondlstream; cooling. said-:vaporproducb sou as "to condense Ahigher boiling-portions thereof while lowery boilinggportions remain'lfin-l the gaseous -phase;- and introducingat least Aa portion-'of saidr gaseous phaseVv materia'l'-intoY said bed at a'level adjacent'ftheelowerendfi thereof and passing-said gaseous phase-material up-V wardly'throughtheflowermost vregions of said bedftoef; feet cooling of :the 'catalyst there; removing catalyst from" said bed at a level a substantialdistanceabove `tl1`e-1e`vel at Which-said gaseous phase materialwis supplied and; below the levels at which hydrocarbon charge-anderecycledcondensate-areintroduced to lthe bed; Withdraw- Ving the gaseous phaseematerial from-saidLbedvat a'level substantially above l-its point of introduction `but; -bel'ow the level owithdrawal of-"catalyst vand re-introducing at" least a portion'vof'this gaseous phasevmaterial intovthc b'ed'at a' level above the level ofcatalyst withdrawal; re-

generating-thecatalystso withdrawngto etect'recondif Honing/thereof and'fheati-ng of the catalyst to a= tema per-ature\-withinthe range-`about^900"to 1200' F; and` returning said catalyst to said bed asy said second stream; withdrawingcatalyst from-the bottom of saidbedand returningity tothe upperfend thereof as said first stream. 

1. A PROCESS FOR THE CATALYST CRACKING OF HYDROCARBONS TO FORM A GASOLINE-CONTAINING PRODUCT, WHICH COMPRISES: MAINTAINING A DOWMWARDLY GRAVITATING, SUBSTANTIALLY COMPACT BED OF SOLID, GRANULAR ADSORPTIVE CATALYST WITHIN A CONFINED ZONE; SUPPLYING A STREAM OF COOL GRANULAR ADSORPTIVE CATALYST TO THE UPPER SECTION OF SAID BED AT AT TEMPERATURE WITHIN THE RANGE ABOUT 150* F. TO 450* F.; SUPPLYING A STREAM OF HOT GRANULAR ADSORPTIVE CATALYST AT A TEMPERATURE WITHIN THE RANGE ABOUT 900 TO 1200* F. TO AN INTERMEDIASTE LEVEL IN SAID BED IN SUFFICIENT QUANTITY THAT A SUBSTANTIAL PORTION OF SAID BED THEREBELOW IN MAINTAINED AT AN AVERAGE TEMPERATURE WITHIN THE RANGE OF ABOUT 700 TO 1000* F.; INTRODUCING HYDROCARBONS CHARGE INTO THE BED BELOW THE LEVEL OF HOT CATALYST SUPPLY AND PASSING THE CHARGE THROUGH THE BED TO EFFECT CRACKING THEREOF BELOW THE LEVEL OF HOT CATALYST SUPPLY; PASSING VAPORS RESULTING FROM THE CRACKING CONVERSION UPWARDLY THROUGH THE UPPER SECTION OF SAID BED ABOVE THE LEVEL OF HOT CATALYST SUPING OF THE VAPORS TO A POINT WHERE CONDENSTION OCCURS TO THE EXTENT THAT OF THE REMAINING UNCONDENSED VAPOR AT LEAST 75 PER CENT BOILS WITHIN THE GASOLINE BOILING RANGE AND BELOW; REMOVING A VAPOR PRODUCT, AT LEAST 75 PER CENT OF WHICH CONSISTS OF MATERIAL BOILING WITHIN THE GASOLINE RANGE AND BELOW, FROM THE UPPER SECTION OF SAID CONFINED AONE; CONTINUOUSLY REMOVING CATALYST FROM THE LOWER SECTION OF THE BED AS A MIXTURE OF CATALYST PARTICLES INITIALLY SUPPLIED TO THE UPPER SECTION OF THE BED AND CATALYST PARTICLES SUPPLIED AT THE INTERMEDIATE LEVEL IN THE BED; PASSING A PORTION OF THE CATALYST SO REMOVED TOI A CONFINED REGENERATION ZONE AND REGENERATING THE CATALYST THEREIN TO RECONDITION IT FOR RE-USE IN THE REACTION ZONE; RETURNING CATALYST FROM THE REGENERATION ZONE TO THE BED AS THE HOT CATALYST STREAM; PASSING A SECOND PORTION OF THE CATALYST REMOVED FROM THE BED INTO AND THROUGH A COOLING ZONE AND RETURNING SAID SECOND PORTION TO THE REACTION ZONE AS THE COOL CATALYST STREAM. 